Washington DC, 2043. Ten years after a massive terror attack that ended 300.000 human lives. The US became a closed, surveillance state to prevent potential attacks from the outside. People gave up their privacy and identity for more safety and security. The US and the other world powers have heavily upgraded arms. Mistrust and skepticism between the countries have led to a new cold war in which the latest developments in technology are channeled into the development of new weapons.

Mechs - maned robots - and drones comb through the dark, chaotic streets of Washington DC, fighting terror groups, fanatic religious brotherhoods who prophesise the end of the world and normal people who fight for their freedom.

We focus on two main characters, Edwin Jacobs and his younger brother Samuel.

Edwin is the head of Nucleus Inc., the world leader in terms of cloning and biomechanics technology. He followed the footsteps of his father, who was killed in the terror attack 10 years ago. Samuel joined the army years ago, hoping for a chance to avenge his father's death. But his hopes are crushed as he is injured in a mech-fight against resistance forces. In the midst of chaos, a mysterious group appears, claiming responsibility for the terrorist attack 10 years ago, which they named "Day of Admonition". They announce that their next assault will exceed the last one by far. Meanwhile Samuel, maimed and disabled, falls into a deep depression, crippled by his inability to take revenge on the enemy which killed his father.

A young woman appears and offers Samuel her help. She claims to be a member of MOTHER, a shadowy organization that seems to be equipped with incredibly advanced technology. Samuel joins MOTHER and begins training to use their technologies and weapons - huge mechs unlike anything Samuel has seen before. Together with the other pilots, Samuel awaits the war against the enemy who killed so many people and who's motives remain so mysterious. Only their name is known... THE LAST CAUSE.

In the meantime Edwin has his own reasons to investigate what MOTHER is, discovering a connection with his own company. Apparently Nucleus Inc. is only the tip of a hidden pyramid. While Samuel and the other pilots are preparing for war, Edwin immerses himself in espionage and deceit on the trail of an unimaginable conspiracy, and poised to uncover a dark secret...